1. FIELD OF THE INVENTION
The present invention relates to discoidal polyphase brushless DC synchronous motors and generators, polyphase AC synchronous motors, polyphase AC synchronous induction motors and generators and polyphase AC induction motors with a radial rotor cage. The above polyphase brushless DC and AC synchronous machines are based on an inverted stator/rotor configuration with an open frame structure for high capacity.
Polyphase brushless DC and AC synchronous motors/generators are characterized by a discoidal single or dual rotor, armature coil windings, coils being wound in rectangles around a laminated core or cores of a single or dual stator with every third, fourth, fifth or sixth coil connected into a series/parallel polyphase configuration on the periphery of the stator with alternating polarity facing alternating field poles on the rotor and separated by a minimal axial air gap between the stator and the rotor.
2. DESCRIPTION OF THE PRIOR ART
Conventional DC machines with a wound rotor and wound field poles or with permanent magnet field poles require brush type commutations, are relatively heavy, have a large size per unit of power and require constant maintenance with high operating costs. Brush type DC motors are gradually being replaced by more advanced brushless DC motors or AC induction motors with variable frequency controllers.
Almost 80% of three-phase AC synchronous and induction squirrel cage motors and generators are used in industrial and commercial applications, in hydroelectric power generating stations, and in mobile diesel or turbogenerating power units with relatively low maintenance and operating costs. However, they are not without their drawbacks since machines with higher power ratings have higher power losses and have an increased size and weight per unit of power due to the larger size in the frame structure needed for magnetic flux circulation and heat dissipation for the relatively high current carrying capacity of heavy copper conductor machines. The efficiency of a large machine is directly related to the machine design characteristics, power losses, iron core losses, copper losses, windage losses, stray losses and :heat (I.sup.2 R) losses. The inclusion of DC and AC inverter and frequency controllers raise the maintenance and operating costs and cause higher power losses.